I would agree that heating the space with gas does generate water vapour as
I found out in my previous but over time it dried out the building and the
condensation (mostly on the inside of main outside windows, I just kept the
sash window slightly open to provide air flow) was a lot less than when I
first moved in. Gas heaters have a drying effect on the air.

1) +1 to have celling fans to draw the cold air up and then push the warm
air down. It also has the added bonus it can cool the space in summer
months.

2) Also believe we should fit a fan heater above the main door to act as a
heat curtain, which will stop that cold rush of air when someone goes to
open the front door.  

3) Also obtain a industrial size dehumidifier to keep the condensation in
check for the whole space (workshop & clean area & kitchen)

Chris